The only way to take PP is if he pays it as a gift, He can not reverse a gift, and you do not pay fees on a gift. BUT if PP ever determines you are taking gifts as payment for goods then PP may terminate your account.
I always print out a bill of sale with a short description, the Serial No, My name, and the buyers name, dates and any other pertinent info. Like a delivered date. It would not hurt to have pics also.
I am guessing that in HI all machine sales are local?